Dental composite restoratives have found wide use as an aesthetic substitute for dental amalgams. However, there is need to improve the durability and longevity of these materials. Because the final restorative must have handling properties that are acceptable to the dentist, any method used to improve the properties of the restorative must not significantly increase the viscosity. The addition of linear polymers to dental composites increases the physical properties of restoratives; however, a concomitant increase in viscosity is often observed which impedes the clinical application of these materials. However, hyperbranched polymers, a new class of high-branched polymeric materials, maintain relatively low solution or melt viscosities that do not increase significantly with increases in molecular weight. This proposal will establish the ability of methacrylated commercial hyperbranced polymers to improve the properties of dental restoratives while maintaining a low, functional viscosity. Following these preliminary studies, high performance hyperbranced polymers, rigidified though intramolecular hydrogen bonding, will be synthesized to further enhance the properties of the restoratives. These modified hyperbranced polymers will be formulated with BisGMA-TEGDMA and the physical properties will be evaluated using standard techniques. It is anticipated that the hyperbranced modified BisGMA-TEGDMA will demonstrate the improved properties that can be expected from high molecular weight polymers but these materials will not experience any significant increase in viscosity.